Even though both processors are different physically – one is a dual core, and one is a quad core, they both run on a 1333MHz system bus (333MHz FSB). Our testing shows that the way AI Gear 3+ controls the FSB with either processor is the same.

In maximum performance saving mode, AI Gear 3+ drops the FSB to 300MHz. However, similar to our findings with the Core 2 Duo E4500, the multiplier is locked to 6x irregardless of CPU load, which is the multiplier activated when C1E/EIST kicks in.

E8400:

QX9650:

Switching to medium performance saving mode increases the FSB to 317MHz, but still below the default FSB of 333MHz. For this setting, the multiplier is not locked to 6x at all times. On load, the multiplier is set back to the processor default of 9x.

E8400:

QX9650:

High performance mode is essentially running without AI Gear 3+, but leaving C1E/EIST enabled in the BIOS.

E8400:

QX9650:

Turbo mode overclocks the FSB to 350MHz. This results in the processor being slightly overclocked as well on load. On idle, the multiplier drops to 6x and raises back up to 9x on load. This behavior is similar to the other modes with the exception of the maximum power saving mode where the multiplier is locked to 6x at all times.